Method for correction of color images

ABSTRACT

COLOR IMAGES PRODUCED BY DYEING GELATIN RELIEFS CONTAINING SILVER ARE COLOR CORRECTED BY REHALOGENATING THE GELATIN RELIEF AND THEN SUBJECTING IT TO A TANNING DEVELOPMENT. THIS TREATMENT CONTROLS THE DYE-ABSORBING ABILITY OF THE GELATIN RELIEF.

Sept. 4, 1973 j SEIICHI TAGUCHI ET AL 3,756,817

METHOD FOR CORRECTIUN OF COLOR IMAGES Filed Sept. 9, 1971 HG. j b

Int. Cl. G03f 3/00, 3/04; G03c /44 U.S. CI. 96-12 16 Claims ABSTRACT OFTHE DISCLOSURE Color images produced by dyeing gelatin reliefscontaining silver are color corrected by rehalogenating the gelatinrelief and then subjecting it to a tanning development. This treatmentcontrols the dye-absorbing ability of the gelatin relief.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates generally to a method for the correction of color images andmore particularly it is concerned with a novel process for correctingcolors, gradations, or optical densities in the formation of colorimages by a dye transfer process.

Description of the prior art A dye transfer process has hitherto beenknown and is fundamentally composed of the following four steps: (1)engraving, (2) dyeing, (3) rinsing, and (4) dye transferring.

The engraving step is also called a matrix making step and generallymeans such a step that a color negative film is printed on panchromaticmatrix films (the main constituent of the film is composed of adispersion of silver halide and pigment in unhardened gelatin) by athree-color separation system. The films are then subjected to tanningdevelopment and fixing so that a relief is formed on the films. In thetanning development, the areas of the film exposed to light areblackened and the unhardened gelatin of the film is hardened inproportion to the blackening. The fixing of the film is conducted byusing a fixing solution containing sodium thiosulfate as the maincomponent and containing no hardening agent. The formation of relief isconducted by removing the areas of the film with hot water that have notbeen exposed to light, i.e., those areas Where the gelatin has not beenhardened.

The dyeing step is a step of dyeing the gelatin of the matrix preparedin Step 1. In general, in this step each of a set of three matricesseparated by lights of blue, green, and red is dyed in the correspondingcolor, i.e., dyed by a dyeing solution of yellow, magenta, or cyan dyerespectively.

In the rinsing step, the excessive dyeing solution having no relation tothe image, which has attached on the surface of the matrix thus dyed isremoved.

In the dye transfer step, a dye-receiving paper having a mordantedgelatin layer is closely brought into contact with the gelatin layer ofthe matrix prepared above, whereby the dye in the matrix is transferredonto the dyereceiving paper. By transferring the dye images of yellow,magenta, and cyan successively onto a same image-receiving paper whilestrictly conforming the positions of the images, a natural colorpositive image can be obtained.

For adjusting the color, gradation, or density of the color image in thecase of making the color image by the "United States Patent 0 ice dyetransfer process as mentioned above, the following six methods havehitherto been known:

Method 1: By adjusting the pH of the dyeing solution, the amount of thedye to be adsorbed on the matrix is adjusted.

Method 2: By adjusting the pH of the rinsing solution, the amount ofremoval of the dye adsorbed on the matrix is adjusted.

Method 3: If the amount to be corrected is large, the exposure of thepanchromatic matrix film is conducted again.

Method 4: If it is necessary to correct a part of the image, the film isexposed again while covering partially other areas than the part to becorrected.

Method 5: The undyed matrix is treated with an aqueous potassiumpermanganate solution to modify locally the gelatin layer, whereby thepower of the gelatin layer absorbing the dye is weakened to thenecessary extent.

Method 6: A necessary amount of the dye is removed from the matrix dyedby means of a brush containing a washing solution having a pH valuehigher than that of the dyeing solution.

These conventional methods have the following demerits respectively:

Method 1: It is difficult to maintain grey balance.

Method 2: The maintenance of grey balance is difficult and uneven dyeingis apt to occur.

Method 3: This method requires additional materials and difficulties areencountered.

Method 4: This method requires additional troubles and period of time.

Method 5: The control for the treatment is difiicult and uneven dyeingis apt to occur.

Method 6: The control for the treatment is diflicult and the treatmentrequires great skill. In case a large number of duplicates are to beproduced, each duplicate must be retouched by hand, which reduces thereproducibility.

SUMMARY OF THE INVENTION It is the object of this invention to provide amethod for correcting color images Without the accompanying demerits asmentioned above.

The inventors have discovered that when a matrix having a relief isprocessed with a rehalogenation bath and then again developed with atanning developing solution, the gelatin in the matrix is greatlymodified and the absorbing ability of the gelatin for dye is remarkablydisturbed. By applying such a phenomenon as discovered by the inventors,the method of this invention for correcting the color images by a dyetransfer process has been accomplished. Thus, the invention is a methodfor correcting color images which comprises, in case of making the colorimages by a dye transfer process, rehalogenating the gelatin reliefcontaining silver and then subjecting the gelatin relief to a tanningdevelopment to control the dye-absorbing ability of the gelatin relief.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of the process of thisinvention is explained by referring to the accompanying drawings inwhich FIG. 1 shows three views each illustrating the method of thisinvention and FIG. 2 is a graph showing the merits obtained by themethod of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1(a) is a cross sectionalview of a sheet having a gelatin relief image 11 on a support 10prepared by a tanning development, fixing and wash-off process. Silverhas been formed in the gelatin relief. The sheet is processed in ableaching solution for silver, whereby the silver present in the reliefis rehalogenated as shown in FIG. tion. For instance, a tanningdeveloping solution contain- 1(b). Thereafter, the sheet is developedagain in a taning pyrogallol, catechol, etc., may be emp'oyed. ningdeveloping solution whereby the gelatin of the relief The correctionprocess of this invention may be applied image is modified and has alowered adsorptive ability to elther the whole image or a part of theimage. In case for dye as shown in FIG. 1(c). By conducting the dyeing 5of correcting the whole color image, the matrix is reand dyetransferring by using the matrices thus prepared halogenated by, preferably, immersing the whole matrix according to the ordinary manner, acorrected color image In the rehalogfifiatlng SoilltlOIl- A180, 111 casef correctis obtained. ing the color image locally, the rehalogenatingsolution By repeating the silver bleaching-tanning developing may beapplied to the necessary part of the color image steps as mentionedabove, the color image can be corby using a brush or the like. Such anoperation can be rected to a d i d t t, Thi i h wn i FIG, 2 i conductedby persons skilled in the art without difiiculty. which the opticaldensity is plotted to the logarithm of ThematriX Corrected desirably ythe Process of thls the exposure amount (abscissa). In FIG. 2 the curve1 is VfifltlOIl can be Used as in the s Of a sual ma X- thecharacteristic curve in the case where a matrix having Examples ofdyeing step and dye transferring step are a relief prepared by anordinary manner is dyed and dyeshown below.

TABLE 1 Dyeing soluti0n Cyan Magenta Yellow. Dye Anthraquinone Blue AB(0.1.03010) Antln'equinone Rubinol R eoncen- Tartrazine (0.1. 19140) 2.0grants. 1.5 grams. trated (0.1. 68215) 3.0 grams.

Sodium hydrogenphosphate 7.5 grams 12.5 grams 20.0 grams. Borax 7.0grams 5.0 grams 2.2 grams. Formalin (37% aqueous solution)... 10milliliters 10 milliliters. 10 milliliters. Water to make 1liter 1liter. u 1 iter. Dyeing time at C minute. 5 minutes 5 minutes Dyetransferring time at 20 C .do ..do Do.

transfered. Also, each of the cuves 2, 3 and 4 is the According to theprocess of this invention, the aforecharacteristic curve of the casewhere a matrix having a said six demerits common to the conventionalmethod relief is subjected, once, twice or thrice respectively, to shownbefore can be remarkably improved, that is to say, the bleach-tanningdevelopment steps of this invention the following demerits:

and then dyed and dye transferred. From the results (1) the maintenanceof grey balance is dimcult, shown 1n FIG. 2 1t will be understood thatthe density and (2) they require much skin, materials and time,gradation of color images can be controlled by repeatedly (3) the colorimage is apt to become uneven. applying the process of this invention. t

The gelatin relief used in the process of this invention The math reasoh15 111 e Polht that the @0101 "P may be composed of gelatin alone or maycontain other 95 can he eorreeted Proporhoh t0 the amount of Sliver highmolecular weight material. For instance, gelatin con- Present the matrlxcorresponding to the amount of mining about 0 to 0% by Weight ofpolyvinyl alcohol posure. It is also an important feature for practicalpuror polyvinyl pyrrolidone may be used The Weight ratio poses that theoperation of this process can be carried out of silver to gelatin in thegelatin relief is 1 to 3. Thus, m hght room Without the necessity of adark room the term gelatin relief means the relief made of such 0 as mmethods 3 and gelatin or gelatin composition Also, by the process ofthis invention the color image The silver bleaching solution orrehalogenation soluof the matrix is corrected Permanently and hence thetion used in this invention is an ordinary silver dye bleach- Process ofthis invention is Particularly effectively applied ing solution used ingeneral photographic processings to the case of reproducing a largenumber of duplicates.

That is to Say, the silver bleaching Solution contains an Furthremore,1t 15 also a feature of this invention that oxidizing agent and ahalide. The typical example of the there occurs no remarkable unnaturalperipheral coloring rehalogenating solution has, for instance, thefollowing whlch apt to occur at the ease of Partial Printing Whilecomposition covering other portions than the necessary areas.

Rehalogenating solution Now, the invention is described more in detailby the following examples.

Potassmm ferrocyanide g 30 EXAMPLE 1 Potassium bromide g 10 Water liter1 This example is the case of applying the method of this invention tothe control of gradation.

A commercially available matrix film was wedge-exposed to red light andsubjected to tanning development,

Rehalogenating Solution 2: (a mixture of the following Solution A,Solution B and water in a ratio of 1:1:5 is

used). 5 fi xing and relief making according to conventional Solution A;methods. The matrix thus processed was dyed according Potassiumbichromate g 20 to the treatment by the cyan dyeing solution shown inConcentrated sulfuric acid ml 14 Table 1 described above and thensubjected to washing Water liter 1 and dye transferring to obtain thewedge image of cyan Solution B: color. The contrast of the image was1.36. Then, the

Sodium chloride .g. 45 matrix was immersed for 1 minute at 20 C. in there- Water liter 1 halogenating Solution I mentioned above and afterwashing with water, the matrix was developed for 2 minutes at 20 C. 1nthe tanning developing solution having the following composition:

Rehalogenating Solution 3: (a mixture of the following Solution A andSolution B in a ratio of 1:1 is used).

Solution A: G Copper sulfate g 160 Pyrogallol Water liter 1 Sodiumhydroxide 3 Solution B: s Ammonium chloride 1.5 Potassium bromide g 100Potassium bromide 15 Potassium bichromate g 2 Citric acid 0:2 Waterliter 1 Water, 1 liter.

The tanning developing solution used in the process of After waterwashing, the matrix was dyed as mentioned this invention may be anordinary tanning developing soluabove, washed, and then subjected to dyetransfer step to obtain the wedge image of cyan color. The contrast ofthe image was 1.05.

Similarly, the processings of the silver bleaching step and the tanningdeveloping step were conducted repeatedly. The contrast of the wedgeimage of cyan color when the processings were conducted twice was 0.84and that of the wedge image when the processings were conducted thricewas 0.75.

By applying the process as above to general color originals to controlthe contrast of the color image good reproductions can be obtained.

EXAMPLE 2 This example is the case of applying the method of thisinvention to color correction.

After conducting similar procedures to the above example using a colororiginal having colors of the skin and blue sky, only the part of bluesky image of the magenta matrix obtained by green separation was treatedwith the rehalogenation Solution 2 mentioned above by means of a brushfor removing excess magenta dye at the blue sky image portion and then,after water washing, was developed for 2 minutes at 20 C. in the tanningdeveloping soution having the following composition:

Catechol 7 Sodium hydroxide 3 Ammonium chloride 1.5 Potassium bromide1.5 Citric acid 0.2

Water, 1 liter.

By conducting the reproduction of color images by using the matrix thusobtained, a preferred color image having the color of a less reddishblue sky was obtained. When the color of the skin was maintained at adesirable color, the green optical density of the portion of the bluesky image was improved to 0.5 from a density of 0.3 before thecorrection treatment.

What we claim is:

1. In a method for forming a color image using the dye transfer processwhich comprises preparing at least one gelatin-relief-image-containingmatrix from a silver halide light-sensitive gelatin containing element,

applying a dye to said gelatin-relief-image-containing matrix, and

transferring said dye from said gelatin-relief-imagecontaining matrix toa receptor surface to form said color image, the improvement whichcomprises, prior to said applying of said dye, correcting said colorimage by rehalogenating a portion of or all of saidgelatin-re1ief-image-containing matrix, and then subjecting saidrehalogenated gelatinrelief-image-containing matrix to a tanningdevelopment whereby the dye adsorbing ability of saidgelatin-reliefimage-containing matrix is controlled.

2. A method for forming a color image as claimed in claim 1, wherein theweight ratio of silver to gelatin in the gelatin-relief-image-containingmatrix is 1 to 3.

3. A method for forming a color image as claimed in claim 1, whereinsaid gelatin-relief-image-containing matrix is gelatin alone, gelatinand polyvinyl alcohol or gelatin and polyvinyl pyrrolidone.

4. A method for forming a color image as claimed in claim 3, whereinsaid gelatin-relief-image-containing matrix contains about to 10% byweight of polyvinyl alcohol.

5. A method for forming a color image as claimed in claim 3, whereinsaid gelatin-relief-image-containing matrix contains about 0 to 10% byweight of polyvinyl pyrrolidone.

6. A method for forming a color image as claimed in claim 1, whereinsaid rehalogenation solution contains an oxidizing agent and a halide.

7. A method for forming a color image as claimed in claim 6, whereinsaid oxidizing agent is potassium ferrocyanide, potassium bichromate,concentrated sulfuric acid or copper sulfate.

8. A method for forming a color image as claimed in claim 6, whereinsaid halide is potassium bromide or sodium bromide.

9 A method for forming a color image as claimed in claim 1, wherein saidtanning development solution contains pyrogallol or catechol.

10. A method for forming a color image as claimed in claim 1, whereinsaid method comprises preparing one said gelatin-relief-image-containingmatrix, whereby a mono-color image is formed.

11. A method for forming a color image as claimed in claim 1, whereinsaid method comprises preparing mul tiplegelatin-relief-image-containing matrices, applying a different dye toeach of said gelatin-relief-image-containing matrices, and transferringeach of said dyes from each of said gelatin-relief-image-containingmatrices to a receptor surface, whereby a multicolor image is formed.

12. A method for forming a color image as claimed in claim 1, whereinsaid method comprises preparing multiple complementarygelatin-relief-image-containing matrices, applying a different dye toeach of said gelatinrelief-image-containing matrices, and transferringeach of said dyes from each of said gelatin-relief-image-containingmatrices to a receptor surface, to form a multicolor image.

13. A method for forming a color image as claimed in claim 1, whereinsaid method comprises preparing complementarygelatin-relief-image-containing matrices, applying a different butcomplementary dye to each of said gelatin-relief-image-containingmatrices, and sequentially and superimposedly transferring each of saiddyes from each of said gelatin-relief-image-containing matrices to areceptor surface, whereby a multicolor image is formed.

14. A method for forming a color image as claimed in claim 1, whereinsaid method comprises preparing three complementarygelatin-relief-image-containing matrices, applying a different butcomplementary dye to each of said gelatin-relief-image-containingmatrices, and sequentially and superimposedly transferring each of saiddyes from each of said gelatin-relief-image-containing matrices to areceptor surface, to form a multicolored image.

15. A method for forming a color image as claimed in claim 14, whereinone of said gelatin-relief-image-containing matrices corresponds to theyellow portion of said image, wherein one of saidgelatin-relief-image-containing matrices corresponds to the red portionof said image, and wherein one of said gelatin-relief-image-containingmatrices corresponds to the blue portion of said image, and wherein ayellow dye is applied to said gelatin-reliefimage-containing martixcorresponding to the yellow portion of said image, wherein a red dye isapplied to said gelatin-relief-image-containing matrix corresponding tothe red portion of said image, and wherein a blue dye is applied to saidgelatin-relief-image-containing matrix corresponding to the blue portionof said image.

16. A method for forming a color image as claimed in claim 1, whereinsaid rehalogenating is repeated.

References Cited UNITED STATES PATENTS 1,923,764 8/1933 Troland 96-362,244,589 6/ 1941 Yankel 96-12 2,607,684 8/1952 Nowak et a1 96-362,814,565 11/1957 Long 96-12 NORMAN G. TORCHIN, Primary Examiner A. T.SURO PICO, Assistant Examiner

